inline 6 runs good for aprox 30 min then looses spark.let it sit for about 20 min starts up runs great another few goes by dies out. whatever is causing it is not exciting the coil. im thinking crank sensor. does not loose fuel press. def a spark issue. distributer and coil all check out ok. gota be a sensor somewhere any advice appreciated . did a search read about ten pages and getting tired of reading

 

OK, quick and easy test will send you in the right direction.

1) using a test light check to see that you have battery voltage with the key on at the coil. If you do proceed to step 2. If you don't run a jumper from the battery to the coil an attempt to start engine. If starts then chase and repair broken wire from ASD relay to coil.

2) using the same test light ,but hook the lead to the battery posititve clamp. Back probe the ground wire for the coil and have someone try to start the vehicle. You should see a steady consistant blinking of the test light to indicate the ecm sending firing signal. If no blinking light ...replace crank sensor. If light blinks go to step 3

3)unplug cam sensor located in the base of distributor housing. Using a multimeter with the key on verify 5volts on ecm reference wire. Verifiy good ground at the sensor. Back probe the sensor return signal wire and set multi meter to ac voltage signal. Have someone crank vehicle. If working correctly you should see a 2.4volt to 0.3 volt voltage sweep . If no signal replace cam sensor. If no 5 volt reference check for broken wire from cam sensor to ecm. If no ground check brown wire with black chaser for loose or broken connection. If voltages are correct replace distributor.(shorted internally)